RDMA/core: Depend on device_add() to add device attributes

Instead of adding/removing device attribute files, depend on device_add()
which considers adding these device files based on NULL terminated
attributes group array.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

include/rdma/ib_verbs.h

@@ -2536,6 +2536,9 @@ struct ib_device {
 
 	struct module               *owner;
 	struct device                dev;
+	/* First group for device attributes, NULL terminated array */
+	const struct attribute_group	*groups[2];
+
 	struct kobject               *ports_parent;
 	struct list_head             port_list;